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Commercial pilot · ACS CA.VI.A · lesson pack

Pilotage and Dead Reckoning

Why this one matters

Most navigation accidents aren't about being slightly off course: they're about running out of fuel, flying into terrain or weather while unsure of position, or a GPS failure the pilot couldn't back up. Pilotage and dead reckoning are the backup that always works, and the habit of comparing plan to actual catches a problem while there are still options.

1 · Know these cold

  • •Pilotage is navigating by visible landmarks; dead reckoning is navigating by computed heading, groundspeed and time. Use them together and cross-check.(PHAK (FAA-H-8083-25C), Navigation)
  • •From true course: apply wind correction to get true heading, variation to get magnetic heading ("east is least, west is best"), deviation to get compass heading.(PHAK (FAA-H-8083-25C), Navigation)
  • •True airspeed is higher than indicated as altitude rises (roughly 2% per 1,000 feet); plan with TAS from the POH for the altitude and temperature.(PHAK (FAA-H-8083-25C), Navigation)
  • •Compass errors in the northern hemisphere: turning errors, greatest on north and south headings (undershoot north, overshoot south), and acceleration errors on east and west headings only (accelerate north, decelerate south). Read it only in steady, unaccelerated flight.(PHAK (FAA-H-8083-25C), Flight Instruments (magnetic compass))
  • •Keep a flight log: actual times over checkpoints, revised groundspeed and ETA, and fuel against plan. Revise early.(PHAK (FAA-H-8083-25C), Navigation)
  • •Commercial standard: within 2 nm of the planned route, checkpoints within 3 minutes of the ETA, altitude ±100 feet, heading ±10°.(Commercial Pilot ACS (FAA-S-ACS-7B), CA.VI.A.S5-S7)
  • •Watch fuel against the plan; VFR reserve is 30 minutes by day and 45 at night, and a commercial pilot plans more than the minimum.(14 CFR 91.151)

2 · The lesson

The plan
  • Choose a route that avoids terrain, airspace and long stretches without landing options; choose altitudes for terrain clearance, winds and cloud clearance. More than 3,000 feet above the surface, the hemispheric rule: magnetic course 0-179°, odd thousands plus 500 MSL (3,500, 5,500); 180-359°, even thousands plus 500 (4,500, 6,500), unless ATC assigns otherwise.(PHAK (FAA-H-8083-25C), Navigation; 14 CFR 91.159)
  • Pick checkpoints that are unmistakable from the air: a river bend, a highway interchange, a lake, a town with a distinctive shape. Space them about every 10 to 15 minutes.(PHAK (FAA-H-8083-25C), Navigation)
  • Read the topography on the chart: contour shading, maximum elevation figures, towers and obstacles near your route.(PHAK (FAA-H-8083-25C), Navigation)
Plotting it
  • Measure the true course, apply the wind correction angle from the forecast winds, then variation and deviation to get the compass heading.(PHAK (FAA-H-8083-25C), Navigation)
  • Compute groundspeed, time and fuel for each leg with your E6B or app; use TAS for the planned altitude and temperature (density altitude raises TAS for the same indicated speed).(PHAK (FAA-H-8083-25C), Navigation)
  • Set power and mixture by the POH for the planned cruise; the fuel burn in the plan only holds if you fly that power setting.(PHAK (FAA-H-8083-25C), Navigation)
Plan versus actual
  • At each checkpoint, note the time; compare with the plan to get the real groundspeed and a revised ETA and fuel figure.(PHAK (FAA-H-8083-25C), Navigation)
  • Drift, by the 1-in-60 rule: each nm off course per 60 nm flown is about 1° of drift. To parallel the course, add the drift angle; to reach the destination, add the drift angle plus a closing angle (distance off per 60 nm remaining). Hold the original wind correction plus that total. Small, early corrections beat large late ones.(PHAK (FAA-H-8083-25C), Navigation)
  • Turns to headings on the compass, northern hemisphere: turning toward north the card leads (shows the turn too soon), so stop the turn early, by 15° plus half your latitude (about 35° at 40° N); turning toward south it lags, so let it pass south by the same amount before rolling out. Read it only in steady, unaccelerated flight.(PHAK (FAA-H-8083-25C), Flight Instruments (magnetic compass))
  • Fuel burning faster than planned (headwinds, wrong mixture, a leak): recompute the reserve and divert early rather than late.(14 CFR 91.151; RMH)
Eyes outside
  • Navigation pulls your eyes to the chart and the log: keep scanning in short sections, and use flight following.(AC 90-48, Pilots' Role in Collision Avoidance)
  • Prioritize: aviate (altitude, heading), navigate (where am I), communicate. A wrong landmark identification often comes from forcing the ground to fit the chart.(Risk Management Handbook (FAA-H-8083-2A))

Want it all on one page, with scenarios? Read the full lesson.

On the flight

ACS standards

  • Prepare and use a flight log; navigate by pilotage and by computed headings, groundspeeds and elapsed time; use the magnetic compass for turns to headings.(Commercial Pilot ACS (FAA-S-ACS-7B), CA.VI.A.S1-S4)
  • Within 2 nm of the planned route; checkpoints within 3 minutes of the ETA, with a destination estimate; altitude ±100 feet, heading ±10°.(Commercial Pilot ACS (FAA-S-ACS-7B), CA.VI.A.S5-S7)

What your instructor is watching for

Your instructor watches for a usable flight log, wind-corrected headings, checkpoint times recorded and ETAs revised, early course corrections, compass turns flown correctly, and altitude and heading within commercial tolerances.

3 · Say it out loud

Answer each one out loud, then check yourself and mark how it went.

  1. Remember Recall it

    “How do you get from true course to compass heading?”

  2. Understand Explain why

    “Why do you revise the ETA at each checkpoint?”

  3. Apply Use it on a flight

    “Two checkpoints in, you're 6 minutes behind plan and burning fuel as planned per hour. What do you do?”

4 · Common mistakes

  • Not recording checkpoint times.

    Without them there's no real groundspeed and no good lost-procedure starting point.

    Instead: Write the time at every checkpoint.

  • Reading the compass in a turn.

    Turning and acceleration errors make it wrong.

    Instead: Use the heading indicator in turns; read the compass in steady flight.

  • Planning with indicated, not true, airspeed.

    Groundspeed and times come out wrong at altitude.

    Instead: Plan with TAS for the altitude and temperature.

5 · Quick check

Answer, then reveal. Flag anything you want to see again.

  1. 1. What is dead reckoning?

  2. 2. East or west variation: which do you add?

  3. 3. In the northern hemisphere, what happens to the compass when you accelerate on an easterly heading?

  4. 4. What are the commercial navigation tolerances?

  5. Scenario5. You'll arrive with 25 minutes of fuel on a VFR night flight. What do you do?

Trained it? Now prove it: practice pilotage and dead reckoning out loud with our examiner.

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Connect it

One situation that runs across this lesson and its neighbors in the same ACS area. Decide first, then check.

Connect it · Navigation

A night cross-country. Headwinds are stronger than forecast and your groundspeed is down 25 knots.

How do your checkpoint times feed a diversion decision? Decide, then see the worked answer

Compare the actual time at each checkpoint with the plan. A 25-knot shortfall stretches every leg, so recompute the fuel to the destination at the actual groundspeed. Keep the reserve separate: 91.151(a)(2) requires enough fuel at night to reach the destination and then fly 45 more minutes at normal cruising speed, so add 45 minutes at normal cruise on top of the destination fuel. That's the legal floor; a personal minimum can raise it but never lower it. If you'd land with less than your minimum, divert now, while you still know exactly where you are. At night, choose the alternate with the Chart Supplement: runway lighting and how it's activated, runway length and surface, and whether fuel is actually available at that hour. Note the time and heading as you turn, estimate heading, time and fuel to the new airport, then refine. Leaving it late, at night, is how being short of fuel turns into being lost.

14 CFR 91.151; PHAK (FAA-H-8083-25C), Navigation; Chart Supplement

Brings together: Pilotage and Dead Reckoning · Diversion

Teaching this? The instructor lesson plan →

Study aid, not FAA guidance. Sources: Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C); Advanced Avionics Handbook (FAA-H-8083-6); Aeronautical Information Manual (AIM); 14 CFR Part 91; AC 90-48 and AC 91-78; Commercial Pilot ACS (FAA-S-ACS-7B). Checked against current sources 2026-11-13.